1. Field of the Invention
The present invention relates generally to the field of electronic data filtering. In another aspect the invention concerns a system for filtering contour-sensitive seismic data.
2. Discussion of Prior Art
The detection of hydrocarbon contacts, zones of diagenetic cementation, and anomalous pressure are common problems in oil and gas exploration and production. Seismic data can often yield insights as to where these geologic features occur in time or depth. However, one problem with using seismic data to detect hydrocarbon contact, zones of diagenetic cementation, and anomalous pressure is that often seismic attributes, such as amplitude, interval velocity, and AVO class, are localized and highly variable due to lateral lithology changes and seismic noise.
Typically seismic attribute maps are presented as 2-D flat images or may be draped on the structural surface along which they were extracted. Typically, the filtering of data used to generate seismic attribute maps is done for a user specified area, without regard for time or depth. Such filtering without regard for time or depth can cause smearing of elevation-sensitive (i.e., contour-sensitive) data across structural (contour) boundaries.
It is, therefore, and object of the present invention to provide a data filtering system for contour-sensitive data that minimizes data smearing along structural (contour) boundaries.
Other objects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments, claims, and drawing figures.
In accordance with one embodiment of the present invention, there is provided a method of filtering contour-sensitive attribute data comprising the steps of: (a) generating a contour map of a physical structure; (b) generating an attribute map of the physical structure, with the attribute map being substantially coincident with the contour map; (c) defining a contour filter band that is limited to a certain range of contour values; and (d) filtering the attribute map using only attribute values that are located within the contour filter band.
In accordance with a further embodiment of the present invention, there is provided a method of filtering contour-sensitive seismic data comprising the steps of: (a) generating a contour map of a subterranean structure; (b) generating a seismic attribute map of the subterranean structure, with the attribute map being defined by a plurality of attribute data points that are substantially coincident with the contour map; (c) selecting a reference point from the attribute data points; (d) defining a filter zone around the reference point; (e) defining a contour filter band within the filter zone, with the contour filter band being limited to a certain range of contour values; and (f) calculating a filtered attribute value for the reference point based on the values of all attribute data points located within the contour filter band.
In accordance with another embodiment of the present invention, there is provided a computer-implemented method of filtering contour-sensitive seismic data comprising the steps of: (a) generating a topographical map of a subterranean structure, with the map being defined by a plurality of seismic data points each having a unique position relative to orthogonal X, Y, and Z coordinate axes, the X and Y axes having units of distance, the Z axis having units of contour value; (b) assigning a seismic attribute value to each seismic data point; (c) selecting a reference point from the seismic data points; (d) defining a filter zone around the reference point, with the filter zone being defined along the X and Y axes; (e) defining a contour filter band for the seismic data points located within the filter zone, with the contour filter band being defined along the Z axis; and (f) calculating a filtered attribute value for the reference point based on all seismic data points located within the contour filter band.
In still another embodiment of the present invention, there is provided a program storage device readable by a computer. The device tangibly embodies a program of instructions executable by the computer for filtering contour-sensitive seismic data. The program of instructions comprises the steps of: (a) generating a contour map of a subterranean structure; (b) generating a seismic attribute map of the subterranean structure, with the attribute map being defined by a plurality of attribute data points that are substantially coincident with the contour map; (c) selecting a reference point from the attribute data points; (d) defining a filter zone around the reference point; (e) defining a contour filter band within the filter zone, with the contour filter band being limited to a certain range of contour values; and (f) calculating a filtered attribute value for the reference point based on the values of all attribute data points located within the contour filter band.
In yet another embodiment of the present invention, there is provided an apparatus for filtering contour-sensitive seismic data. The apparatus comprises a computer programmed to carry out the following method steps: (a) generating a contour map of a subterranean structure; (b) generating a seismic attribute map of the subterranean structure, with the attribute map being defined by a plurality of attribute data points that are substantially coincident with the contour map; (c) selecting a reference point from the attribute data points; (d) defining a filter zone around the reference point; (e) defining a contour filter band within the filter zone, with the contour filter band being limited to a certain range of contour values; and (f) calculating a filtered attribute value for the reference point based on the values of all attribute data points located within the contour filter band.